Polymerizable compositions

Abstract

PCT No. PCT/GB92/02079 Sec. 371 Date Oct. 4, 1994 Sec. 102(e) Date Oct. 4, 1994 PCT Filed Nov. 11, 1992 PCT Pub. No. WO93/10159 PCT Pub. Date May 27, 1993.A polymeric dispersant having a low Tg polymer component, e.g. polybutadiene, and a pendant silylated group with hydrolyzable groups capable of associating with and dispersing finely divided inorganic fillers. Curable compositions containing the polymeric dispersant can be cured into composite materials having improved resistance to stress induced by thermal cycling.

We claim: 
     
       1. A polymeric dispersant comprising (a) a polymeric component containing at least one segment of low Tg polymeric material having a Tg of less than 0° C., said polymeric component being a vinyl aromatic/conjugated diene block copolymer and (b) silicon containing groups of the formula (I) ##STR3## which are pendant from the polymeric component and wherein X is a hydrolysable group, Y is a hydrocarbyl radical,   a is an integer of 1 to 3   b is 0 or an integer of 1 to 2 and a+b equals 3,   Z is a group resulting from the reaction of an anhydride functional group pendant from the polymeric component and an amino silane precursor and   W is a direct bond or a hydrocarbyl radical containing from 1 to 20 carbon atoms.   
     
     
       2. A polymeric dispersant as claimed in claim 1 wherein X is selected from halogen, alkyl carboxylate, alkoxy carbonyl and lower hydrocarbyl radicals. 
     
     
       3. A polymeric dispersant as claimed in either claim 1 or claim 2 wherein Y is an alkyl radical. 
     
     
       4. A polymeric dispersant as claimed in claim 1 wherein the functional group is pendant from the at least one segment of low Tg polymeric material. 
     
     
       5. A polymeric dispersant as claimed in claim 1 wherein the polymeric component comprises polybutadiene units. 
     
     
       6. A polymeric dispersant as claimed in claim 1 wherein the at least one segment of low Tg polymeric material has a molecular weight greater than 5000. 
     
     
       7. A polymeric dispersant according to claim 1 wherein W is a hydrocarbyl radical containing a functional group. 
     
     
       8. A polymeric dispersant according to claim 1 wherein the copolymer is selectively hydrogenated. 
     
     
       9. A polymeric dispersant according to claim 1 prepared by adding aminopropyltriethoxy silane to a solution of maleimized polybutadiene or maleimized styrene-ethylene/butadiene-styrene block copolymer in methyl methacrylate.